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How do I clear only a specific area of a screen (quickly) in machine code ?I'm looking for a machine code routine which will clear the first 20 rows of the Spectrum's display (or any number of rows or columns) . I have found…
Preferred way of determining Y co-ord in assembly?I know of 2 ways of calculating the y-cord of a pixel row for the speccy in assembly. One is to calculate the address by ways of shifting and masking…
... next char boundary
add hl,de ;by adding 32 ... add a, l
ld l, a
ld e,(hl)
inc hl< ...
addx ld a,l
add a, c ;get x ...Project: M.u.l.e.Wokani came up with a great idea about trying an open-development approach for spectrum games, and I thought why not try with a game I have under dev…
... = " ";
char *s1 = "This is a test message that is supposed ... hl
add hl,de
push hl
rl (hl)
dec hl
rl (hl ... Temp\s3g_.opt
z80asm -a -m -Mo -oC:\z88dk\work ... you are trying to convert a pointer to an integer without ...Project: M.u.l.e.Wokani came up with a great idea about trying an open-development approach for spectrum games, and I thought why not try with a game I have under dev…
... the scrolling message works a lot better in Spectaculator ... in Spectaculator there is a hickup in the scrolling ... and blit() functions when a new character is installed. This ... hl
add hl,de
push hl
rl (hl)
dec hl
rl (hl ...Game ideaThinking of a game that could enter the Minigame compo I came to the following idea for a game, although it might not fit 1K or 4K: A mazed snake ga…
...
Anyone willing to add his own defined level???
xor a
ld hl,23560 ; LASTKEY
ld (hl),a ; set impossible ... value
nokey or (hl ...Help hacking Split PersonalitiesI`ve been hacking away at Split Personalities for the purpose of putting new screens and graphics (items). The current screen is at 41187 and is 160…
...
add a,a
jr nz,n6
ld a,(hl)
inc hl
add hl,de
ld c,a
ld b ...48K sound effectsAnybody knows where could I find some small M/C routines to play tiny beeper sounds I could use in the 48K version of a game? I don't want the 48K pl…
... /> di
PlaySFXLoop1
ld a,(CurrLevelPaperColour) ;flip the speaker
hl; hold amplitude for hl cycles
PlaySFXLoop2
dec hl
ld a ... nz,PlaySFXLoop3
pop hl
add hl,bc ;vary the cycle ...Easy Compare On 2 Byte Register?e.g. HL, BC, DE Has anybody got a really easy way of doing this without comparing each byte seperately? Any maths has no effect on the flags as far a…
Well "sbc hl," and "add hl," come to mind for comparisons ... case of sbc, especially, take a long time.
It ... turns out that comparisons a byte at a time is faster on ... />
Anyway you can have a look at what z88dk uses ...Easy Compare On 2 Byte Register?e.g. HL, BC, DE Has anybody got a really easy way of doing this without comparing each byte seperately? Any maths has no effect on the flags as far a…
If you really need COMPARE (that is, content of the registers should remain unchanged), you can do this:
or a
sbc hl,de
add hl,deEasy Compare On 2 Byte Register?e.g. HL, BC, DE Has anybody got a really easy way of doing this without comparing each byte seperately? Any maths has no effect on the flags as far a…
... :
or a
sbc hl,de
add hl,de[/QUOTE]
ADD
and then when condition ... met/not met add again so you need 2 ADD HL,DE
[code]
or a
push hl
sbc hl,de
pop ...Bubble Bobble EditI thought I might have a go at editing Bubble Bobble myself after reading this... [url]http://www.worldofspectrum.org/forums/showthread.php?t=15452[…
...
ld l,a
inc a
cp # ... ,858c
add hl,de
ld a,(hl) ;grab our colours ...
ld hl,#860c ;location ... carry
rl (hl) ;and shift into 860c ...Delay routineAs some people are aware, I have recently starting writing a [url=http://fuse-emulator.svn.sourceforge.net/viewvc/fuse-emulator/trunk/fusetest/]autom…
... hl,-141
add hl,bc
ld bc,-23
.loop add hl,bc ...
jr c,.loop
ld a,l
add a,15 ...Wtf??I won this NZ auction earlier this week [url]http://www.trademe.co.nz/Browse/Listing.aspx?id=116509561[/url] and have been to collect the hardware th…
... 0f 00 $0ats
add hl, bc ; fe84 09 $0bts ... 0ats
[COLOR="Red"]ld a, $81[/COLOR] ; fe89 3e ... /> [COLOR="Red"]out (c), a[/COLOR] ; fe8b ed 79 $ ...
[COLOR="Red"]ld a, $0f[/COLOR] ; fe8d 3e ... /> [COLOR="Red"]out (c), a[/COLOR] ; fe8f ed 79 $ ...Compressors are available for Speccys ?Hi folks, although I was an wasn't strictly a speccy coder in the glory days (amstrad & amiga for the most part), I have secides to arse about with …
...
ld a,(hl)
add hl,bc
ld (hl),a
inc hl
ex ... de,hl
jr ...
ld a,(hl)
add hl,bc
ld (hl),a
inc hl
ex ...Vector drawing routines.Anybody could point me to some sort of vector drawing package of routines, callable from BASIC? With "vector drawing" I mean to draw 2D pictures with…
... left
ld a,b ; within byte
add a,a
or c ...
or b ; a = incoming pixels ... change
or (hl)
ld (hl),a ; fill byte on screen ...Compressors are available for Speccys ?Hi folks, although I was an wasn't strictly a speccy coder in the glory days (amstrad & amiga for the most part), I have secides to arse about with …
...
ld a,(hl)
add hl,bc
ld (hl),a
inc hl
ex ... de,hl
jp ... /> add a,a
ld ixl,a
ret nz
ld a,(hl)
inc hl ...Duel of the games 4! Super conundrum! Manic Miner vs Jet Set WillyGo on I dares ya, to decide which one is best, it's popped up in many, many previous threads, so do it, decide the better of the 2 :D
...
#8B50: ADD HL,DE
#8B51: LD A,(#85CC) ; number of ... /> #8B58: NEG
#8B5A: ADD A,(HL) ; add #1C - lives*4 to pitch ... . Sure, it isn't a correct musical transposition (one could ... implement a tone-chart to transpose each ...Duel of the games 4! Super conundrum! Manic Miner vs Jet Set WillyGo on I dares ya, to decide which one is best, it's popped up in many, many previous threads, so do it, decide the better of the 2 :D
...
#8B50: ADD HL,DE
#8B51: LD A,(#85CC) ; number of ... /> #8B58: NEG
#8B5A: ADD A,(HL) ; add #1C - lives*4 to pitch ... . Sure, it isn't a correct musical transposition (one could ... implement a tone-chart to transpose each ...Compressors are available for Speccys ?Hi folks, although I was an wasn't strictly a speccy coder in the glory days (amstrad & amiga for the most part), I have secides to arse about with …
... dest)
sbc hl,bc
ld a,(hl)
add hl,bc
ex ... de,hl
ld (de),a
sbc hl,bc
ld a,(hl)
add hl,bc
ex ...help sought with first foray into machine code - pixel scrolldownI have started to code my first machine code program, a simple roadrace game. I've based it around the pixel scrolldown routine in 40 Best Machine Co…
... to next line through a char
add hl, de ;goto next line ... through a char boundary
pop ... to
ld hl,$7e0 ;2016 added . . .
add hl, de ;to posn ... to be copied
ex de,hl ;?? ...help sought with first foray into machine code - pixel scrolldownI have started to code my first machine code program, a simple roadrace game. I've based it around the pixel scrolldown routine in 40 Best Machine Co…
... ]Does anyone have a link to a list of how ... /z80-documented.pdf[/url] has a listing.
[ ... address one double byte at a time, right? In ... pop ix
ld hl,-32
add hl,sp
ld (source ... code the scroll in a single monolithic code block ...Interface 1 emulation issuesFor Virtual Spectrum v3.0 I am implementing virtual Interface 1 and Interface 2 options! The I/F2 ROM option works already, and I have got the I/F1 s…
... /> ;
pop hl
ld (err_sp),hl
ld a,$ff
ld ... (err_nr),a
ret ... /> ld h,a
ld b,8
crcbyt add hl,hl
jr ... nc,crcnxt
ld a,h
IF2 Rom snapshot creationHi, is it possible convert a Speccy 16k snapshot to a Interface 2 Rom file? I've the original Ultimate Pssst, Cookie, Trans-am and Jetpac tapes and …
...
LD H,D
ADD HL,HL ;x2
LD C,L ... BC
ADD HL,HL ;x4
ADD HL,HL ;x8
ADD HL,BC ;add BC to make ... L,A
LD H,$00
ADD HL,DE ;now add new digit ... +2),A
LD (reloc4+7),DE ;BC for LDIR
ADD HL ...Bresenhams circle algorithmI post here my final circle code to replace, if you want, the one in the ROM. It only uses integer math and runs very fast and is very compact. It is…
...
add A,H
ld c,A
ld A,E
add A,L ...
ld b,A
add A,L
ld c,A
ld A,E
add A,H ... de,hl
add hl,de
ex de,hl
inc hl ;hl' is ...Design Design / Crystal ComputingNice post on [URL="http://groups.google.com/group/comp.sys.sinclair/browse_thread/thread/56e6ebdedc6930ac#"]comp.sys.sinclair[/URL] about [URL="http:…
... now and it's choc-a-bloc with some excellent ... br /> ret
show ld a,(hl) ; fetch alien status.
... each alien table entry.
add hl,de ; point to next alien ... I spent trying to create a bold font version in ...Changing the way SCREEN$ is loadedThe way the speccy loads in a SCREEN$ is interesting - top two-thirds first, then middle and finally the bottom, which is due to the way the speccy d…
... ; mask
ld (hl), a ; poke colour
inc hl ; next attribute
drawline: ld a, 0 ; a = screen poke byte
ld (hl), a ; poke to ... address
add a, 32 ; add 32
ld (screenaddress+1), a ; poke result ...Spectrum AssemblyHi All, Thanks for letting me in... lol Over the last couple of days I started playing my spectrum emu again and then I started thinking about lear…
... a, (height)
ld ix, lines
ld hl, (y_off)
add hl, hl ...
ex de, hl
add ix, de ...
nextln: push af
ld a, ... (x_off)
add a, (ix+2)
...Spectrum AssemblyHi All, Thanks for letting me in... lol Over the last couple of days I started playing my spectrum emu again and then I started thinking about lear…
... a, (height)
ld ix, lines
ld hl, (y_off)
add hl, hl ...
ex de, hl
add ix, de ...
nextln: push af
ld a, ... (x_off)
add a, (ix+2)
...A scrolling starfield - help needed!I have been messing on my speccy again recently and tried to do a scrolling (parallax - maybe) starfield. I know how to scroll using machine code but…
... 3 most lsb
ADD A,A
ADD A,A ;multiply result by 4 ... L,A ; add the x-coordinate to the low byte of hl ... HL,STARDATA
LD B,0
LD C,A
ADD HL ... ,BC ; add ofset 0-7 ...A scrolling starfield - help needed!I have been messing on my speccy again recently and tried to do a scrolling (parallax - maybe) starfield. I know how to scroll using machine code but…
... ex de,hl ;de=dest,hl=offset
add hl,de ;hl=src,de=dest ... L,A ; add the x-coordinate to the low byte of hl (can ... HL,STARDATA
LD B,0
LD C,A
ADD HL ... ,BC ; add ofset 0-7 to ...
